Rippling muscle syndrome preceding malignant lymphoma

A 46-year-old woman presented with rippling muscle phenomenon. She complained of uncomfortable muscular stiffness of extremities and abdominal wall. Muscle contraction was easily elicited by percussion, which was visible from the surface and propagated in a rolling manner. The mounding (or myoedema) phenomenon was also remarkable. Three years later, malignant lymphoma (histologically, lymphoplasmacytoid lymphoma) was found in the sacrum. The lymphoma subsided with treatment by vincristine, cyclophosphamide, doxorubicin and prednisolone. Serum IgG as well as creatine kinase values were normalized. The rippling phenomenon also responded to the treatment. The present rippling muscle syndrome might be of a paraneoplastic or autoimmune origin related to lymphoma, although the evidence seemed indirect. We discussed the role of the internal membrane system of the skeletal muscle in the pathogenesis of rippling muscle.